Technical Measures for Rapid Propagation of Improved Beef Cattle

Based on early weaning in calves,hormone induction in young calves,intravital egg collection,in-vitro fertilization and embryo transfer which serve as major breakthroughs in livestock breeding technology,the techniques of hormone induction and in-vitro fertilization were integrated,not only to solve the problem of obtaining oocytes by hormone induction in adult cows in production practice,but also to obviously improve production efficiency.The application of this technology can help accelerate the cultivation process,shorten the generation interval,promote the industrialization and improve the economic benefits of beef cattle breed.This paper provides a reference for the research and application of new breeding and propagation techniques of beef cattle.

Effects of changing the control ovarian stimulation protocol in patients without a transplantable embryo in the previous in vitro fertilization/intracytoplasmic sperm injection cycle

Objective:Some patients fail to obtain an embryo for transplantation during previousin vitro fertilization(IVF)or intracytoplasmic sperm injection(ICSI)cycles,and require multiple reproductive treatments.This study aimed to evaluate whether changing the control ovarian stimulation(COS)protocol during the subsequent stimulation cycle could improve laboratory and clinical outcomes in these patients.Methods:Patients without a transplantable embryo(TE)in the previous IVF/ICSI cycles were recruited during their second cycles.They were classified into two groups according to their first cycle protocol:Group A,patients treated with a gonadotropinreleasing hormone agonist(GnRH-a),and Group B,patients treated with a gonadotropin-releasing hormone antagonist(GnRH-ant).The study group included patients whose stimulation protocols were changed,whereas the control group consisted of patients who used the same stimulation protocol in the second cycle.We then compared the numbers of oocytes collected(OC)and TE,the incidence of non-TE,the pregnancy rate(PR),and the live birth rate(LBR).Results:In Group A,the numbers of OC and TE were significantly lower(6.0±4.7vs.9.4±6.4,2.3±2.2vs.4.5±3.8,P<0.05)in the study group compared with those in the control group.In Group B,the numbers of OC and TE were higher(7.0±5.5vs.4.0±4.3,3.5±3.4vs.1.8±2.1,P<0.05)in the study group.There was a significant increase in the incidence of non-TE(adjusted odds ratio(AOR)=2.12,95%CI:1.04–4.69)of the study group in Group A but not in Group B.No significant differences in the PR or LBR were found between the study and control groups in either Group A or B.Conclusion:Changing the COS protocol from GnRH-ant to GnRH-a or continuing the GnRH-a protocol can improve laboratory outcomes in patients with no TE in the previous IVF/ICSI cycle.